Transmittance and attenuance of the water column; Vertical velocity of the water column (currents); Salinity of the water column; Horizontal velocity of the water column (currents); Secchi disk depth; Temperature of the water column

Over 130 surveys were carried out in the Tamar Estuary between 1976 and 1989. Some were simply horizontal surveys of salinity and turbidity, usually sampled 0.5 metres or 0.25 metres above the seabed. Other surveys were over a full tidal cycle and included vertical profiles, with temperature and current velocity also being measured.